A Reaction Scheme Applicable to Combustion of C₁- and C₂-Hydrocarbons

Abstract

A reaction scheme is constructed for the combustion of simple fuels. It comprises C₁ and C₂ species and does not contain higher hydrocarbons. The rate constants are mainly determined on the basis of Westbrook's and Warnatz's reaction schemes, but some of them must be changed to make the scheme comprehensive. This reaction scheme and a mathematical model for one-dimensional premixed flames are applied to methane/air flames under various equivalence ratios and acetylene, ethylene and ethane flames under their stoichiometric conditions. The validity of the proposed scheme is verified by comparing the predicted burning velocities with this scheme and the experimental ones under the corresponding conditions. The mechanism of the combustion reactions in the above hydrocarbon flames are analyzed. In the methane flames, the reaction paths through C₂ species cannot simply be neglected. The reaction scheme where the C₂ species are omitted cannot reproduce the satisfactory burning velocities for these flames. In the acetylene flame, active C₂H₃ radicals are produced at low temperatures and are converted again to C₂H₂ at higher temperatures. In the ethylene flame, C₂H₄ reacts through C₂H₂. In the ethane flame, more than half of C₂H₆ is oxidized through C₁-species reaction paths.